Floor form with connected truss supports

ABSTRACT

A steel joist formwork and a composite steel and concrete floor structure provided with a top chord, a bottom chord and a web joining the top and bottom chords with the top chord being serpentine shaped like an S or Z and including top and bottom, generally horizontal portions and an intermediate portion integrally connecting opposite edges of the top and bottom portions with the top and intermediate portions substantially being adapted to be embedded in the concrete floor to cause the floor and steel joists to act structurally as a composite beam. Either the web or a leg depends vertically from the free end of the bottom portion of the top chord, and the web joining the top and bottom chords is substantially solid or is, an open web formed of a zig-zag bar member. There is also disclosed a building system and erecting method utilizing steel joists spaced apart by spanner bars which also support rigid panels which act as formwork for the pouring of concrete. The spanner bars and the joists are so arranged to cooperate that the spanner bars may be removed together with the rigid panels after the concrete has been poured, and the spanner bars, the rigid panels and if desired the steel joists may be reused for formwork for additional poured concrete construction. Alternatively the joists may be left in place either with the top chords embedded in the poured concrete to provide a composite action, or merely supporting the concrete slab in the conventional fashion. A novel cold rolled sheet steel joist may be advantageously used to form a particularly economical composite system. This steel joist is shaped in an I-beam configuration with an upper top chord bent to have the appearance of the letter Z in cross-section for bonding with the concrete floor.

[ Oct. 15, 1974 FLOOR FORM WITH CONNECTED TRUSS SUPPORTS [75] Inventors:Ernest O. Butts; John'S. Hall, both of Ottawa, Canada [73] Assignee:I-Iambro Structural Systems Limited,

Ottawa, Ontario, Canada 22 Filed: July 24,1972

21 Appl. No.: 274,415

Related U.S. Application Data [60] Division of Ser. No. 220,627, Jan.25, 1972, abandoned, which is a continuation-in-part of Ser.

No. 872,017, Oct. 29, 1969, abandoned, and a continuation-in-part ofSer. No. 145,758, May 21, 1971.

[30] Foreign Application Priority Data Nov, 4, 1968 Canada 034293 [52]U.S. Cl. 249/30, 249/210 [51] Int. Cl E04g 11/38 [58] Field of Search52/321, 694, 648; 249/18, 249/23, 26, 28, 30, 83, 90-91, 93, 210

[56] References Cited UNITED STATES PATENTS 1,974,730 9/1934 Zollinger52/321 2,058,268 10/1936 Stanley 249/24 2,169,253 8/1939 Kotrbaty 52/6932,457,250 12/1948 Macomber 52/694 2,508,635 5/1950 Badt 249/23 3,362,1211/1968 Weber ..52/334 FOREIGN PATENTS OR APPLICATIONS 73,319 6/1960France 189/37 Primary Examiner-Robert D. Baldwin Assistant ExaminerJohnMcQuade Attorney, Agent, or FirmCushman, Darby & Cushman [57] ABSTRACT Asteel joist fomiwork and a composite steel and concrete floor structureprovided with a top chord, a bottom chord and a web joining the topand'bottom chords with the top chord being serpentine shaped like an Sor Z and including top and bottom, generally horizontal portions and anintermediate portion integrally connecting opposite edges of the top andbottom portions with the top and intermediate portions substantiallybeing adapted to be embedded in the concrete floor to cause the floorand steel joists to act structurally as a composite beam. Either the webor a leg depends vertically from the free end of the bottom portion ofthe top chord, and the web joining the top and bottom chords issubstantially solid or is, an open web formed of a zig-zag bar member.There is also dis closed a building system and erecting method utilizingsteel joists spaced apart by spanner bars which also support rigidpanels which act as formwork forthe pouring of concrete. The spannerbars and the joists are so arranged to cooperate that the spanner barsmay be removed together with the rigid panels after the concrete hasbeen poured, and the spanner bars, the rigid panels and if desired the:steel joists may be reused for formwork for additional poured concreteconstruction. Alternatively the joists may be left in place either withthe top chords embedded in the poured concrete to provide a compositeaction, or merely supporting the concrete slab in the conventionalfashion. A novel cold rolled :sheet steel joist may be advantageouslyused to form a particularly economical composite system. This steeljoist is shaped in an l-beam configuration with an upper top chord bentto have the appearance of the letter Z in cross-sectionfor bonding withthe concrete floor.

, 6 Claims, 28 Drawing Figures PATENTEB 1 51914 3.841 .597

sum 8 or a FLOOR FORM WITH CONNECTED TRUSS SUPPORTS This application isa division of Ser. No. 220,627, filed Jan. 25, 1972, which is acontinuation-in-part of both Ser. No. 872,017, filed Oct. 29, 1969, nowabancloned, and Ser. No. 145,758, filed May 21, 1971, U.S. Pat. No.3,819,143, issued June 25, 1974.

i The present invention relates to-a composite floor system and partsand formwork therefor for use in the construction of buildings such aslarge open span buildings. The present invention is particularlyconcerned with composite floor systems and a novel form of open websteel joist for use insuch a floor system.

' In accordance withthe present invention, one form of steel joistcomprises a top chord, a bottom chord and a zig-zag bar web having itsapices welded to the top and bottom chords. The top chord includes afirst flange extending parallel to the plane of the web, a second flangeconnected to the first flange above the web, a third flange obliquelyconnected to the second flange and a fourth flange connected to thethird flange and substantially parallel to-the second flange, thesecond, third and fourth flanges being intended to be partly or whollyembedded in a concrete slab poured on formwork supported by a pluralityof such open web steel joists. For the purpose of supporting suchformwork, openings are provided in the first flange of the steel joistin which spanner bars may be inserted to support the formwork betweenthe open web joists and to stabilize the joists prior to the pouring ofthe concrete.

In accordance with a preferred form of the invention, the concrete slabpoured on the formwork supported from the bar joists is reinforced witha reinforcing'mesh which is draped over thetop flanges of the open websteel joists and hangs in a catenary-like shape between the open webjoists to provide the most effective shape a for shear reinforcement.

The composite floor system utilizing the applicant's novel open webjoists is more economical than conventional open web joists systems andpermits a variety of forming materials. The mesh embedded in theconcrete forms the correct catenary for maximum shear reinforcement ofthe concrete-slab. Plywood forms may be used between the open web joistsgiving a degree of lateral stability before the concrete is poured andthe plywood forms may be reused in subsequent concrete pouringoperations.

A, particularly significant aspect of the invention is that the spacingbetween open web joists may be greatly increased over the spacingspresently utilized, since the spanner bars positioned between'the openweb joists and the joists themselves carry theconstruction loads and thecompleted composite floor system hasadequate strength to carry alldesign loads once the construction has been completed. It will beappreciated that several inherent advantages of composite constructionare obtained; for example, a whole floor or roof assembly when pouredforms a single unit which provides increased strength and stability tothe structure.

it is also within the scope of the present invention to form large spanfloors using the open web joists of the invention. which may be proppedduring construction and which when the composite system has achieved itsultimate strength are capable of supporting the design loads across thefull span without propping.

The present application also relates to building systems and inparticular a building system-in which a combination of open web joists,spanner bars and rigid floor system for use in the design andconstructionof buildings such as large open span buildings in which a"cold rolled sheet steel joist is formed in the shape of an I-beam withan upper chord bent to have the appearance of the letter Z incross-section.

An object of the invention is to provide an economical and strongcomposite floor system bythe use of cold rolled sheet steel members. i

A further object of the invention is to provide a novel spanner or rollbar for use with novel formwork pursuant to the present invention.

A further object of the invention :is to provide a floor system whichcan be adapted to permit efficient and economical erection anddisassembly of a multiple use formwork material to receive the concreteslab of this composite floor system. This is accomplished by the use ofopenings which are cut at regular intervals along the horizontal lengthof the. vertical flange of the cold rolled sheet steel joists into whichthe ends of the span ner bars which are shaped so that they may, by useof a hammer or similar object, be wedged into this opening. Due to theshape of the openings, the removal of the spanner bars is accomplishedby moving the spannerbars in the opposite direction as when they werewedged-in during erection. This latter procedure permits safe andeasyremoval of firstly the spanner bars and secondly theformworkmaterial. Spanner bars and formwork material can then be reused for thesubsequent construction of additional composition floor systemsfollowing the teachings of the present inventionous embodimentsof thepresent invention:

FIG. 1 is a perspective view from below of a composite floor systemutilizing the applicant's novel open web joists,

P16. 3 is a perspective detail illustrating thenotches formed in thefirst flange of the applicant's novel open web joists.

F 10. 4 is an elevational end view of an open web joist of the presentinvention.

FIGS. 5 and 6 are elevational views showing portions of floor systemsutilizing the open web joists of the.

present invention.

chords of this invention with a modified vertical flange,

FIG. is a vertical section through a building system pursuant to thepresent invention;

FIG. 11 is a perspective view partly broken away illustrating removableformwork pursuant to the present invention;

FIG. 12 is a perspective view similar to FIG. 11 illustrating a slightlymodified type of top chord in removable formwork of the invention;

FIG. 13 is a perspective view of yet another form of the reusableformwork system pursuant to the present invention;

FIG. 14 is a perspective view with the panels removed of yet anotherform of reusable formwork of the invention;

FIG. 15 illustrates a less preferred form of elongated slot provided forreceiving the end of a spanner bar;

FIG. 16 illustrates a spanner bar adapted for utilization with theelongated slot of FIG. 15;

FIG. 17 illustrates the preferred form of elongated slot;

FIG. l8illustrates another form of spanner bar;

FIG. 19 illustrates-an alternative form of elongated slot intended forutilization with a spanner bar as illustrated in FIG. 18;

FIGS. 20 and 21 illustrate alternative forms of top chord for the openweb steel joist for utilization with the roll bar illustrated in FIG.22;

FIG. 22 illustrates a roll bar adapted for utilization with the topchords of FIGS. 20 and 21.;

FIG. 23 is a vertical section through a wall form constructed pursuantto the present invention;

FIG. 24 is a perspective view of the back of a wall form pursuant to thepresent invention;

FIG. 25 is a perspective view of a cold rolled sheet steel joist in'accordance with a preferred form of the invention; I

FIG. 26 is a vertical section through a composite floor system usingtheapplicants novel cold rolled steel joists;

FIG. 27 is a vertical section illustrating the spanner bar and novelcold rolled sheet steel joist; and, v

FIG. 28 is a plan view of a spanner bar in accordance with a preferredembodiment of the invention.

In FIG. 1 there is shown in perspective a composite floor systemconstructed in accordance with the present invention. A compisite floorsystem is indicated generally at 10 including a plurality of open web orbar joists I] and a poured concrete slab 12 containing a reinforcingmesh 13. As illustrated in FIG. 1, each of the open web joists llincludes a bottom chord 14, a zigzag or serpentine configured bar web 15and a novel shaped top chord 16 which is described in greater detailbelow.

Positioned between the barjoists 11 are steel spanner bars 17, the ends17' which (see also FIGS. 2, 5, 6 and 28) are offset from either the topor bottom surfaces of the bars and extend through openings 18 formed inthe top chord 16, of the open web joists. For ease in inserting thespanner bar ends, openings 18 have an up- 4 wardly directed leg 18'(FIG. 2) for initially receiving the ends 17 which are then moved ordriven and jammed into the shorter horizontal legs of the openings tolateral provide stability, rigidity, proper joist spacing and concretepouring form support. In the left side of FIG. 1, bars 17 areillustrated in a position supporting a reusable plywood form 19, and inthe right side of FIG. 1, bars 17 are illustrated supporting a steel pan20 of known type.

It will be noted in FIGS. 1 and 2 that knock out portions 21 are shownin the depending legs or vertical flanges 16a of top chords 16 in theopen web joists 11 beneath the ends of the spanner bars 17. These pieces21 are so formed (prescored or the like) during manufacture of the openweb or bar joists 11 that they form knock out panels which can beremoved after the concrete has been poured in the composite floor systemand the spanner bars 17 and the formwork 19 or 20 removed and reused forthe subsequent pouring of additional composite floors following theteachings of the present invention. Alternative and more preferred formsof spanner bar 17 and openings 18 are illustrated in FIGS. 15-19 and 28.It will be appreciated that the size and shape of the opening 18 inwhich the ends of the spanner bar 17 are fitted may depend upon theparticular form of spanner bar used and similarly the size and shape ofthe knockout panel 21 will also vary depending upon the particular typeof spanner bar used. In FIG. 1, spanner bars 17 on the left side of thedrawing are shown with a substantial portion of the bar projecting belowthe apertures or slots 18 (see also FIG. 5), while in the right side ofFIG. 1 (and in FIG. 6) the substantial portion of the bar projects aboveapertures 18. That is, in accordance with a further feature of theinvention, such a shape of spanner bar permits the use of either athicker plywood type panel or form l9 or a thinner sheet metal pan typepanel 20 merely by reversing the position of the bar 17 duringinsertion. For use with the plywood panels, the offset at the ends of 17of the spanner bars is from the lower surface thereof, but for the sheetmetal panels 20 the offset of the spanner bar ends 17 is relative to theupper surface of the bars. It is contemplated that the spanner bars 17normally would be removed from the composite structure and the formworksuch as 19 in FIG. I would be taken away and reused. However, it will beappreciated that a specific application in accordance with the inventionmight include retaining the spanner bars as part of the permanentstructure although normally these bars are removed together with theconcrete supporting formwork once the concrete has set.

In FIG. 2, there is illustrated in perspective, a pair of open web barjoists 26 and 27 (each the same as joists 11 in FIG. 1) and a spannerbar 17. As previously mentioned, the spanner bar openings 18 aredisposed in the depending leg or vertical flange 16a of the top chord 16together with knock out panel 21 which may be removed after the concreteof the composite floor is poured to release the spanner bar 17. In thisembodiment, the novel serpentine shaped top chord 16 has a transversecross-section in the form of the letter Z, i.e., of a zig-zagconfiguration, and includes three integral portions or flanges 16b, 16c,and 16d besides leg 16a. Top and bottom portions 16b and 16d aresuperposed with intermediate portion angling or being disposed obliquelybetween opposite ends of those top and bottom portions. This shapeprovides for greater transfer of load from the slab to the joist andgreatly increased shearing resistance between the top chord and theconcrete floor. Of considerable importance as later described is thefact that leg 16a depends from the free vend or edge 162 of the bottomportion.

In FIG. 3 an alternate form of spanner bar 17 is illustrated asincluding a notch 29 which co-operates with the-sides of the opening 18to increase the structural rigidity of the open web joists and spannerbars during construction as more fully discussed in relation to FIG.

28. This increased rigidity is sufficient to eliminate the requirementfor bottom bridging duringerection and prior to setting of the concrete.The ends 17 of the bars may alternatively be longitudinally wedge shapedif desired;

FIG. 4 is a vertical transverse section or end view through a bar joistconstructedin accordance with the present invention clearly illustratingthe cross-section of the novel top chord 16 of the present invention.The bottom chord 14 which, in this particular joist (and in FIG. 1) isshown as formed of a pair'of rods, is .welded to the bottomapices'ofzig-zag web 15 which in turn is welded at its upper apices tothe top chord 16. As shown, the lower horizontal flange 16d bottoms onthe top of web 15, which is secured against the depending leg orvertical flange 16a for greater stability.

FIGS. 5 and 6 illustrate the use of spanner bars in accordance with thepresent invention to support formwork during the pouring of concrete.FIG. 5 closely resembles the left side of FIG. 1, and FIG. 6 closelyresembles the right side of FIG. 1. As before, open web joists 11support spanner bars 17 above which in FIG. 5 is mounted a plywood form19 andin FIG. 6a steel pan 20. It will be noticed in FIGS. 5 and 6 thatthe same spanner bar is used in both cases but that in FIG. 6 the offsetedge 30 is positioned upwardly whereas in FIG. 5 the offset edge 30 ispositioned facing down. This allows for the difference in thicknessbetween the plywood form 19 and the steel pan 20. Thus-in accordancewith the invention a single type of spanner bar 17 may be used tosupport either plywood, for example, or steel panformwork on'which theconcrete composite floor may be poured. It'will also benoted that thetop chords 16 of the novel open webjoists 11 are substantially embeddedin the concrete floor (though in practice the lower face 16a, andperhaps a short part of intermediate portion 160, may or may not beembedded) and that the reinforcing mesh 13 hangs in acatenary shape uponand between the open web joists 11 providing the proper shearreinforcement for the concrete floor.

FIGS. 7 and 8 illustrate other alternative forms of serpentine shapedtop chords. The Z-shaped top chord 16 of FIGS. 1-6 is altered in FIGS. 7and 8 to a smoothly curved S-shape surmounting the usual vertical flange16a forming an integral top chordl6'. The opposite ends of the upper andlower curved flanges or portions l6b and l6d are integrally connected atopposite edges with the obliquely directed intermediate portion l6'c,and the whole chord is preferably cold rolled steel. In bothembodiments, leg 16a depends from the free end l6e of the bottomportions l6,'d, which in in the vertical leg or flange16a of the openweb joist' for supporting the spanner bar. As before, opening 18 isprovided with a knock out portion 21. In .this case the 6 L-shapedopening 18 is formed with a downwardly directed vertical leg 18' and ahorizontally directed leg so that knock out portion 21 is a smallrectangular member attached at two edges tothe remaining metal of thevertical flange 16a.

' As will become more apparent hereinafter, the vertical leg 18 of theopenings 18 shown in FIGS. 2, 3 and 9 are not absolutely necessary,particularly when the thickness of the ends 17' is less than the heightof opening 18. That is, with such a lesser thickness, the spanner bars17 can be inserted into opening 18 while their breadth is in ahorizontal position, and then the bars can be rotated or rolled into thevertical position shown for bars 17 in FIGS. 13. v I v As discussedbelow with regard to later figures, spanner bars 17 preferably have somesort of handle means to effect such rotation for insertion into andremoval from openings 18.

From the foregoing, it is also apparent that knockouts 21 shown in FIGS.2, 3, and 9 are not basically necessary either as long as the spannerbars 17 can be removed if desired from openings 18 without suchknockouts, I

As previously indicated, the top chords 16 in FIGS. 1-9 above are madeof sheet metal, preferably cold rolled steel, all in one piece.Preferably also, spanner bars 17 are of heavier steel gauge than thesheet metal for top chords 16, for example, the thickness of spannerbars 17 may be in the order of one-quarter inch to one half inch metalplate while top chords 16 are of 10 a may cause some deformation in thevertical legs 16a when the spanner bars are hammered, wedged and/orrolled into place in openings l8.'Thistight'fit greatly improves thestability of the erected joists'beforefconcrete is poured. Generallyspanner bars 17 are of rectangular cross-section with a maximum height,for example, in the order of two to three inches.

Thespacing between adjacent joints which is usually approximately fourfeet, although of course, it'may be any other desired distance. Normallythe joist spacing is considerably greater than with prior artsteeljoist- /concrete slab construction since the slabin thepresent inventiongives a composite action which increases theload bearing capacity beyondthat of the joist above. It should be appreciated that the abovedimensions are given only as representative examples to which limitationis not intended.

As previously mentioned, the vertical legs 16a of top chords 16 dependfrom their respective lower portions 16d at the free or outer edges l6ethereof. As may be readily noted in FIGS. 1 and 2, as well as FIGS. 5and 6, the top chords 16 are all oriented in the same way. For example,as seen in FIG. 1, all of the vertical legs 16a depend on. the left sideof their respective top chords 16. This is shown in greater detail inFIG. 2 from which it is also readily apparent that the intermediateflanges or portions of the two top chords 16 extend obliquely in thesame direction. i.e., both angle upwardly to the left. In other words,the Z configuration of each top chord is oriented in exactly the samemanner as in the next top chord. This means that each spanner bar 17which is disposed between successive top chords is overlaid by only oneof the lower portions 16d of those chords. Consequently, in constructingthe formwork, the plywood panel 19 or steel panel 20 shown in FIGS. 1,and 6 may-have one of its longitudinal edges pushed on the spanner barsunderneath the lower portion 16d, and then the opposite edge of thatplywood or steel panel is dropped or otherwise brought downto rest onthe spanner bars adjacent the opposite leg 16a. This provides for arelatively tight fit of the panel causing a substantially concreteleakproof pouring form, though in fact there may be a one-half inch orso leeway between the panel edges and the legs 16a. Additionally, thisprovides for ready removal of the panels from below after the concretehas set, by merely removing the spanner bars in the manner abovedescribed, allowing the panels to be recovered for reuse if desirediTheplywood forms, which conveniently may be standard 4 foot by 8 footsheets, provide a diaphragm action to further stiffen the floor beforeconcrete is poured. i As is apparent from the foregoing, all. joistsnormally have flush shoes and hence no infilling is required betweenjoists in masonry construction. This leads to a reduction in soundtransmission. In addition, the stiffness of the resulting compositesteel and concrete floor reduces both. vibration and deflection.

Still further embodiments of theinvention are discussed below. i v y InFIG. there is shown a vertical section through a building utilizing aconstruction system of the present invention. As illustrated, there isshown a concrete wall 40 which maybe either poured, masonry, block orcould alternatively be a column placed ahead of the floor system. Oneither side of the wall 40 are placed temporary scaffolds 41 and 42 onthe top ends of which are supported open web steel joists or bar joists43 and 44 which have open webs as previously described.

Supported between successive open .web joists are rigid panels 19, forexample of plywood. These panels span transversely to the joists 43 and44, the ends of the spanner bars being received in openings 18 formed inthe lower edge of the top chord or in the upper part of the web of theopen web joists 43 and 44..

The steps in the process of erecting a building utilizing the buildingsystem of FIG. 10 typically would consist of pouring a floor orfoundation, erecting vertical walls or columns, positioning temporaryscaffolding to support the open web joists, inserting spanner bars andplywood panels between the joists, and pouring the successive floorofthe building. After an appropriate period of time, for example, sevendays, the spanner bars and panels would be stripped from the open webjoists, and after a further period of time, for example 28 days, theopen web joists would be removed, together with thetemporaryscaffolding.This material could then be raised to a higherfloor of the building and reused to make formwork for pouring asucceeding upper floor of the building. The poured concrete floor wouldbe reinforced in the usual way to carry all loads between the verticalwalls and columns.

It should be noted that there is no need for reshoring of the pouredconcrete floors in this system. By allow ing the open web joists toremain in place, the necessity for reshoring is avoided, and thus theconstruction of the building can be accelerated since mechanical tradescan have access to the floor at an earlier date than would be requiredif reshoring were utilized.

As an alternativeform of construction it is within the scope of thepresent invention to support the open web joists as permanent portionsof the building structure, and to incorporate the open web joists aspermanent portions of the building. Such open web joists may either havea conventional top chord having a flat upper surface, or may utilize aform of top chord provided with shear connection to the concrete to givea composite action which results in a significant decrease in the costof building construction as hereinbefore described. It will beappreciated that any poured concrete structure will of course have toinclude reinforcing elements to strengthen the concrete, but for thesake of simplicity such reinforcement has not been illustrated in FIG.10.

With the system of the present invention it is possible to utilizestandard material sized to form the plywood panels and the spacing ofthe open web joists may for example be advantageously fixed atapproximately four foot centers, thereby enabling the use of standard 4x 8 sheets of plywood which are the most inexpensive size commerciallyavailable. It should also be recognized that in accordance withcontemporary construction practice,such plywood panels would be treatedwith a release coating, such as oil, to avoid adherence of the concreteto the panel. Such a release coating enables the ready stripping of theforms from beneath the poured concrete floor with a minimum loss offormwork due to accidental destruction.

As illustrated in FIG. 10, and in other sheets of the drawings, thespanner or roll bars 17 may be equipped with one or more permanenthandles 45 or alternatively such roll bars may be utilized together withremovable handles resembling spanner wrenches which are utilized tograsp the roll bar for rotation during insertion and removal. As furtherdiscussed hereinbelow, the roll bars areformed of a material of asubstantially rectangular cross-section and are suitably notched at theends to stabilize the positioning ,of the joists during construction.Additionally, the plywood panels utilized together with the roll barsserve to give a diaphragm action to reinforce the formwork againsthorizontal loads during pouring of the concrete floors.

ln FlG. 11 there is illustrated in perspective a section of formworkused in a building system pursuant to the present invention asillustrated in FlG. 10. The open web joist 43 supports a spanner bar orroll bar 17 on which a rigid plywood panel 19 is positioned. A likepanel 19A is positioned on the opposite side of the open web joist 43from the panel 19 and is supported by a spanner bar (not illustrated).The form of open web joists shown in FIG. 11 utilizes a hat" section topchord which hasa substantially flat upper surface 60 and horizontallyextending flanges 61 and 62 to support the edges of the plywood forms19A and l9respectively. Aportion of an elongated opening 18 is alsoillustratedin the drawing.

FIG. 12 illustrates an alternative form of top chord which is providedwith a flat upper surface 63 with one long vertical leg 64 and a shortvertical leg 65. As before, the long vertical leg is provided withelongated openings 18 for cooperation with the roll bars 17which supportpanels 19, and 19A.

FIG. 13 illustrates an alternative embodiment of the invention utilizingan alternative form of top chord for each of the open web joists 43 andin which a second (lower) roll bar 17 is utilized to connect the bottomwhere necessary for strengthening the formwork. As

before, the plywoodpanel19 is supported by the upper roll bar 17 andfits between, and have its upper surface substantially flush with, thetops of the top chords of joists 43. It will be noted that the form oftop chord illustrated in FIG. 13 (also partially shown in FIG. 21)includes a channel 66 with upwardly extending lips' 67 positioned ateither side of the joist into which the method ends of the upper rollbars 17 are fitted. Between successive lips 67 in this channel, notchesare provided at appropriate locations so that the roll bars may beremoved after'pouring of the concretefloor.

FIG. 14 illustrates another alternative embodiment of the invention inwhich the top chord is formed in the shape of an inverted channelwith'elongated openings for cooperation with the ends of the roll bars17, and a bridging bar 25 is provided connecting the bottom chord of theopen web joist which bottom chord is formed by-a pair of angles with aspace therebetween.

FIGS. 15, 17 and 19 illustrate other configurations of elongated opening18 formed in the side of the joist for supporting of any of the spannerbars shown in FIGS. 2, 3, 16, 18, 22 or 28. FIG. 17 illustrates themostpreferred shape of opening 18 and is especially well adapted for usewith the spanner bar of FIG. 28.

FIG. 16 illustrates a form of spanner or roll bar 17 formed ofrectangular cross-section material with an inverted triangular shapednotch 26 in each end of the bar 17, while in FIGS. 18 and 22 notches 26are rectangular and respectively in the upper andlower surfaces of thebars. Preferably the notches 26 in the-spanner bars of FIGS. 18 and 22have a width slightly greater than the gauge of the top chord material.In use bar 17 is turned with handles 55 so that the flat side of thematerial extends in the long direction of the hole 18, and the bar maythen'be inserted in the hole-and rotated sov that the sides of the notch26 engage the bottomedges -of the hole 18 to fix the bar in relation tothe hole 18.

FIG. 20 illustrates another form of top chord which might beutilized'with spanner bars of shape illustrated in FIG. 22. In this casethe notches 26 are formed in the lower edge of the spanner bar and sit'on'the upturned lips 28 of the top chord of the open web joist.

FIG. 21 illustrates a shape of top chord also shown in FIG. 13 which hasa channel 66 provided with upturned lips 67 to cooperate with a spannerbar such as that illustrated in FIG. 22.

FIG. 23 illustrates the application of the principles of l the presentinvention to erect formwork for vertical constructions such as thepouring of concrete walls. FIG. 24 is a perspectivefrom one side of theformwork illustrated in FIG. 23, and the two figures of drawings will bedescribed together for simplicity. A vertically extending member 50which resembles an open web joist of tapering depth is positionedvertically and provided with a channel 51 with a plurality of elongatedopenings 52. Spanner or roll bars 53 are inserted in the openings 52 inthe channel 51 and serve to support of the spanner bars and the panelsand subsequently by removal of the vertical reinforcing members 50.

- In FIG. 25, there is shown in perspective a joist 110 constructed of asingle piece of cold rolled sheet steel in accordance with the presentinvention. The joist is generally in I beam form and includes a bottomchord 111 which may, for example, have in a generally rectangular shape,a vertical flange 112 and a generally 2- shaped top chord 113. Inerecting; the composite floor system described in FIGS. 26 and 27,special cold rolled sheet steel joists 110, in a similarly oriented andproperly spaced parallel relationship, are supported at opposite endsupon anyusual and conventional sup ports.

Positioned between two such novel joists 110 are spanner bars 114 whichmay have tapered and notched ends 115 and shown in FIG. 16, or conformto the preferred shape FIG. 28. The ends 115 cooperate with the taperedopenings 116 in the vertical leg or flange-112 and are wedged intoopenings 116 during erection. The plurality of openings 116 arerectangular in shape with one side so tapered from the bottom to the topthat when spanner bar end 115 is inserted and hammered into the opening116 spanner bar 114 becomes wedged securely. Preferably the rollbar orspanner bar 114 are provided'with handles 120 to assist in positioningthe roll bar during erection. Supported on the spanner bar 114 is thereusable formwork 119 which is effectively sealed against loss of wetconcrete by the return lip or bottom portion of the Z-shape of the topchord 113 and the vertical face 112 of the opposite joist 110. I Oncethe spanner bars are removed the openings 1 16 may serve as pass-waysfor electrical and mechanical conduits thereby permitting a saving inthe height re-. rs bstwssmflqstsv The top chords 113 of this novel joist1111 I ded in the concrete floor 117 which is part of this comrigidpanels 54 from outward motion. A bottom tie consisting of a pipe spacer56 is provided at the base of the wallform and a top tie 56 ispositioned at the top of the wallform. As before the concrete wall ispoured the shape being retained by the formwork and after the concretehas set the formwork is stripped by removal posite floor system, and thereinforcing mesh 1'18 hangs in a catenar'y shape between the noveljoists to provide a proper reinforcement for the concrete slab. Thus theconcrete slab becomes part of the top chgd FIG. 28 is a dimensioned planof a roll baror spanner bar which is the most preferred form forcommercial use. As shown, the roll bar is formed of V2 inch thick steelplate and has an overall length of 4 ft. 5 inches. Slots 131 and 132 arespaced apart 4 ft. 1 /4 inches so that standard 4 foot shets of plywoodmay be used for formwork. The slots 131 and 132 are approximately %inchdeep and slightly wider than the gauge of sheet steel used in formingthe top chord of the beams. One end 133 projects 4 inches beyond theleft end slot 131 of the bar 130 and the other end 134 projects V2 inchbeyond the slot 132. A pair of handles 135 and 136 are tack welded tothe roll bar 130 to facilitate insertion and removal of the roll bar130. The extended end 133 has proven to be very useful for supportingshort sections of formwork where insufficient room is available for afull length roll bar. Other advantages in the use of this form of rollbar are readily apparent to those involved in the construction ofbuildings pursuant to the teachings of this application, p

Further modifications will become apparent to those acquainted with thisart and such are to be included in the scope of this invention asdefined claims.

by the following,

1 l I We claim:

1. In formwork for constructing a composite steel and concrete floor,the combination which comprises:

a steel joist having top chord means, a bottom chord, and web meansjoining and separating the top chord means and the bottom chord; saidtochord means including v a top portion generally horizontally disposedrelative to said web means, a lower portion generally horizontallydisposed relative to and extending along thetopof said webmeans, and jan intermediate portion connecting said top por' tion to said lowerportion, said intermediate portion extending obliquely between the topand lower portions .to connect one edge of the top portion to theopposite edge of the lower portion;

said joist having means extending vertically below the other edge ofsaid lower portion for connecting said top chord means and web means;

at least an additional steel joist substantially alike thefirst-mentioned steel joist, the additional steel joist being laterallyspaced from and extending parallel to the first-mentioned steel joistwith the said intermediate portion of each top chord means of bothjoistsextending in the same oblique direction so that the said opposite edgesof the respective lower portions of each top chord means extend alongthe same side of the respective joists and the said vertically extendingmeans of each joist extends horizontally along the corresponding otherside of each said joists; j at least two spanner bars extendinglaterally between and being connected to s'aid've'rtically extending oneedge of said pouring form being underneath and held down by the saidlower portion of the top chord means of one of said joists while beingdirectly supported as aforesaid by said bars closely adjacent said onelower joist lower top chord portion, so that a concrete slab may bepoured upon the form to embed the top chords down adjacent the level ofthe lower portions thereof to create a composite steel and concretefloor below which the web means and lower chords of the steel joistsdepend, with the aforesaid substantially rigid, horizontally extendingheld down and directly. supported pouring form contributing to thedevelopment of diaphragm action in and hence lateral stability of saidformwork both before any concrete pouring and during the setting of apoured concrete floor.

2. The combination of claim 1 wherein each top chord means includes saidvertically extending means in the form of a'flange depending verticallyfrom and integral with the said other edge of said lower portionthereof; each vertically depending flange having notch meanstherethrough for receiving respective ends of the spanner bars forconnecting the spanner bars to the steel joist top chords and effectingsaid predetermined distance spacing.-

3. Formwork for a poured concrete floor comprising:

a plurality of metal joists, each joist having top and bottom chords andintervening connecting means,

said top chords being shaped substantially as an S or Z in transversecross section, I means for supporting said joists in parallel spacedrelation with their said shaped parts oriented in the same way, rigidpanels substantially filling the space between the connecting means ofadjacent joists with one edge of each panel being underneath and beingheld 'down by'one of said top chord shaped-parts, and

at least two bars per panel directly supporting said panels level andholding said one edge of each panel substantially up against itsrespective one of 4 said top chord shaped parts, said'bars extendingbetween the said connecting means of adjacent joists with the oppositeends of the bars being removably qhsls ten s e ..ssmssfiaamsan .i. thearrangement being such that the pouring form contributes to thedevelopment of diaphragm action in and hence lateral stability of saidformwork before any concrete pouring and during the setting of a pouredconcrete floor.

4. Formwork as in claim 3 wherein, in each said joist, said connectingmeans is integral with said top and bottom chords and depends verticallyfrom the lower free 5949! salsiloa.hrl.shame part. i

integral with said top and bottom chords.

i l l k a UNITED STATES PATENT OFFICE CERTIFICATE OF GORRECTION PATENTNO. 3'84l'597 D E i October 15, 1974 INVENTOR( I Ernest O. Butts andJohn S. Hall It is certified that error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

In the heading re "Related U.S. Application Data" Item [60] should becorrected and read as follows:

This application is a division of Serial No, 220,627, filed January 25,1972,

which is a continuationin-part of both Serial No. 872,017, filed October29, 1969, now abandoned, and Serial Noo 145,758, filed May 21, 1971, andPatent:

No. 3,819,143, issued June 25, 197

Signed and Sealed this nineteenth D y of Augusr1975 [SEAL] Arrest:

RUTH C. MASON C MARSHALL DANN Allcslmg ()j'jrrer ('mnmr'ssl'mwrufParenrs and Trademarks

1. In formwork for constructing a composite steel and concrete floor,the combination which comprises: a steel joist having top chord means, abottom chord, and web means joining and separating the top chord meansand the bottom chord; said to chord means including: a top portiongenerally horizontally disposed relative to said web means, a lowerportion generally horizontally disposed relative to and extending alongthe top of said web means, and an intermediate portion connecting saidtop portion to said lower portion, said intermediate portion extendingobliquely between the top and lower portions to connect one edge of thetop portion to the opposite edge of the lower portion; said joist havingmeans extending vertically below the other edge of said lower portionfor connecting said top chord means and web means; at least anadditional steel joist substantially alike the first-mentioned steeljoist, the additional steel joist being laterally spaced from andextending parallel to the firstmentioned steel joist with the saidintermediate portion of each top chord means of both joists extending inthe same oblique direction so that the said opposite edges of therespective lower portions of each top chord means extend along the sameside of the respective joists and the said vertically extending means ofeach joist extends horizontally along the corresponding other side ofeach said joists; at least two spanner bars extending laterally betweenand being connected to said vertically extending means of each of saidfirst-mentioned and additional steel joists for spacing said verticallyextending means a predetermined distance apart, the tops of said barsbeing a given height below the said lower portion of each steel joist;and a substantially rigid pouring form having a thickness ofsubstantially said given height, said form being supported directly bythe spanner bars and having a width of substantially said predetermineddistance extending horizontally substantially from said verticallyextending means of the first-mentioned steel joist substantially to saidvertically extending means of the additional steel joist with one edgeof said pouring form being underneath and held down by the said lowerportion of the top chord means of one of said joists while beingdirectly supported as aforesaid by said bars closely adjacent said onelower joist lower top chord portion, so that a concrete slab may bepoured upon the form to embed the top chords down adjacent the level ofthe lower portions thereof to create a composite steel and concretefloor below which the web means and lower chords of the steel joistsdepend, with the aforesaid substantiallY rigid, horizontally extendingheld down and directly supported pouring form contributing to thedevelopment of diaphragm action in and hence lateral stability of saidformwork both before any concrete pouring and during the setting of apoured concrete floor.
 2. The combination of claim 1 wherein each topchord means includes said vertically extending means in the form of aflange depending vertically from and integral with the said other edgeof said lower portion thereof; each vertically depending flange havingnotch means therethrough for receiving respective ends of the spannerbars for connecting the spanner bars to the steel joist top chords andeffecting said predetermined distance spacing.
 3. Formwork for a pouredconcrete floor comprising: a plurality of metal joists, each joisthaving top and bottom chords and intervening connecting means, said topchords being shaped substantially as an S or Z in transverse crosssection, means for supporting said joists in parallel spaced relationwith their said shaped parts oriented in the same way, rigid panelssubstantially filling the space between the connecting means of adjacentjoists with one edge of each panel being underneath and being held downby one of said top chord shaped parts, and at least two bars per paneldirectly supporting said panels level and holding said one edge of eachpanel substantially up against its respective one of said top chordshaped parts, said bars extending between the said connecting means ofadjacent joists with the opposite ends of the bars being removably heldto the respective connecting means, the arrangement being such that thepouring form contributes to the development of diaphragm action in andhence lateral stability of said formwork before any concrete pouring andduring the setting of a poured concrete floor.
 4. Formwork as in claim 3wherein, in each said joist, said connecting means is integral with saidtop and bottom chords and depends vertically from the lower free end ofsaid top chord shaped part.
 5. Formwork as in claim 3 wherein saidconnecting means for each said joist includes a respective vertical legintegrally depending from the lower outer end of said top chord shapedpart, said rigid panels extending substantially between adjacent ones ofsaid vertical legs.
 6. The combination of claim 1 wherein said web meansincludes said vertically extending means and is integral with said topand bottom chords.